Table 4:

Correlation coefficient matrix of Heavy metals in serum of the control and RA patients

Studied Group	Characters	Age	Gender	Pb	Cd	Cr	Ni
RA n=200	Gender	.146*
		.039
	Pb	.026	.036
		.716	.617
	Cd	−.003	−.012	.248**
		.966	.861	.000
	Cr	.016	.184**	−.002	.189**
		.826	.009	.974	.007
	Ni	.003	.167*	.054	−.161*	.106
		.961	.018	.451	.023	.135
Control n=200	Gender	.005
		.943
	Pb	.073	−.134
		.303	.059
	Cd	.087	.126	−.012
		.219	.075	.868
	Cr	−.148*	−.075	.103	−.063
		.037	.294	.146	.375
	Ni	.193**	−.088	−.039	−.016	−.214**
		.006	.217	.582	.827	.002

Upper values indicated Pearson’s correlation coefficient; Lower values indicated level of significance at 5% probability.

^*= Significant (P<0.05);

^**= Highly significant (P<0.01)